There may not be actual giant bipedal humanoids wandering the wilderness, but that hasn't stopped Bigfoot fanatics from coming up with some seriously weird theories explaining all those footprints and blurry videos.

While Bigfoot seems like a North American phenomenon, there are tales of giant wildmen around the world, from the Tibetan Yeti to the Australian Yowie and Siberia's Chunchunya. Could these creatures really be endemic worldwide? Or is there some deep part of the human psyche that peers into the wilderness and sees not something alien, but rather a horrifying reflection of what we could have been (and might still be) without the thin veneer of "civilization" we've wrapped ourselves in?

Here are the five weirdest theories of what's really going on when people report a Bigfoot sighting.

Theory One: Bigfoot represents a lost species of hominid.
On the surface, this theory doesn't seem that crazy. The deep forests and remote mountains of the world could hide a few evolutionary offshoots. It's a lot harder to hide a sustainable population, though. Within a single habitat, any population below about 500 would be considered severely endangered. While it is technically possible such populations of large primates could exist in several places throughout North America and have escaped detection (no confirmed carcasses, bones, scat, or abandoned nests), it is incredibly unlikely. And trying to explain away the scientific implausibility of this theory gives rise to the increasingly arcane theories that follow.

Theory Two: Bigfoot is a Native American nature spirit.
I know it's culturally insensitive to include this on a list of "bizarre" theories, but cloaking an idea in religion or tradition doesn't make it any less ridiculous. In an early issue of the Bigfoot newsletter The Track Record, Gayle Highpine surveyed the various attitudes of North American tribes toward Bigfoot. Lakota, Dakota and Ojibway consider him a spirit guide and harbinger who brings "signs or messages that there is a need to change, a need to cleanse." One Dakota tribe member told a local newspaper, "They exist in another dimension from us, but can appear in this dimension whenever they have a reason to."

Highpine also alludes to a common Bigfoot theme – psychic powers:

The existence of Bigfoot is taken for granted throughout Native North America, and so are his powerful psychic abilities. [Native elders] say that Bigfoot knows when humans are searching for him and that he chooses when and to whom to make an appearance, and that his psychic powers account for his ability to elude the white man's efforts to capture him or hunt him down.

In the 2002 documentary Bigfootville, Native Americans in Oklahoma claimed that Bigfoot could be standing right in front of you, but he could make you not see him with his "magic hypnosis powers."

Theory Three: Bigfoot is an alien creature.
At some point, researchers started noticing that Bigfoot sightings often seemed to be accompanied by strange lights in the sky. The conclusion: Bigfoot is so hard to find because he arrives on his spaceship, makes some footprints, then flies back home. There's more to it than just a vague statistical connection, though. Sometimes Bigfoot seems to be under the control of some other species of alien. In a 1997 interview with Big Foot Encounters, researcher Peter Gutilla related the following story about a rural Seattle man's experience:

Under hypnosis he told of watching two UFOnauts descend from beneath a huge hovering disk-shaped UFO and walk casually into the woods followed by a tall, hair-covered ape-like creature that seemed subservient to them. For weeks preceding the experience the witness said he was often roused at night by a loud whirring noise that originated in the sky above trees near his home. Neighbors also heard the sound which was recorded on tape, and in one of the recordings a high-pitched wailing cry can be heard behind the drone of the sound-maker.

Theory Four: Bigfoot is an invisible psychic monster from another dimension.
Some Bigfoot sightings have been accompanied not by lights in the sky, but rather weird flashes of light in the woods. Also, sometimes his massive footprints just end, as if he was walking along and just disappeared. Some people even claim to have seen a Bigfoot vanish into thin air. Therefore, he must be warping in and out of our dimension.

John Cotton, vice president of the Canadian Society of Questers, in a 1997 news article in Utah's Deseret News, described Bigfoot as a "hairy angel" who comes to our dimension to impart some kind of vital knowledge to shamans. The subject of the article was a man named Ron Mower, who claimed to have seen otherdimensional Bigfoot nine times. He warned that there were good and evil Bigfoots, but they are helpfully color-coded – the bad ones have red eyes. Mower also believed that Bigfoot had teleported himself to Mower's home to stalk him there.

It gets better though. So much better. A story posted to Cryptomundo in 2007 made astonishing claims about government research on otherdimensional Bigfoot. You should really go read the whole post, but in summary: In the 60s and 70s, Livermore Labs and UC Berkeley captured a pair of Bigfoots, but they escaped through the 4th dimension and wandered the lab for weeks invisibly, scaring the secretaries, who were the only ones who could detect them on account of their natural female sensitivity to the electromagnetic clouds produced by the entities. Finally, the government took all the research notes and is suppressing all Bigfoot information and research. The kicker? Stephen Hawking was there, and we could prove all of this if only anyone had the balls to ask him about it.

Theory Five: Bigfoot is human...with really nice hair.
This theory relates to one specific Bigfoot sighting, the famous Patterson film (above). I'll admit, even in the face of (contested) declarations that it was a hoax, it's hard to watch that film and not feel a shred of doubt. You can convince yourself that it isn't just a guy in a costume if you watch it enough times. What else could it be? Well, if you look closely, you can see that the creature in the film has breasts. It also has a prominent sagittal crest on its head, which gives it a somewhat coneheaded appearance. The problem is that sagittal crests generally appear on males in large primates, while large, furry, pendulous breasts suggest the creature is female. How to sort out this apparent inconsistency?

Close analysis of still frames has revealed (to some people) that the bulge on top of the head isn't a sagittal crest at all. It's a beehive hairdo.

While this seems ludicrous, it does perhaps lead to a more plausible theory, at least in regard to this one sighting. Could it be a human woman born with several congenital disorders? Hypertrichosis, gigantism, perhaps a bone growth disorder? In a rural area, she might have been abandoned at a young age, yet somehow managed to survive as a feral child. It's a bizarre and incredibly unlikely series of events.

I guess Bigfoot really must be an invisible psychic 4D shaman, after all.